Moneypit Posted July 11, 2020 Share Posted July 11, 2020 Hello everyone, I have a 1997 mack ch613 with the 427. If the truck sits for more than 24 hours I have to use the hand primer to start it. Which I've been doing for a while. Starts perfect after hitting the primer 7 or 8 times. Only doing this in the morning. But starts like it should all day. Last week at idle my truck started popping. Already change fuel filters twice. Doesn't loose power when driving. It only does it when I stop sometimes. It may run for 2 hours with no problems then starting sputtering the rest of the day at idle. Get over 1,000 rpms and it clears up. It's not smoking. Does this sound like hand primer, hole in rubber lines, injector or etc. Bout to work on it in the morning. Just wondering which one yall would start at first. Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/63268-sucking-air-into-fuel-system-or/ Share on other sites More sharing options...
mrsmackpaul Posted July 11, 2020 Share Posted July 11, 2020 Put a slight amount of air pressure on the tank (10-20psi) and then look to see if any fuel is leaking out of the system I use a bit of old inner tube and a hose clamp to hold it on the filler neck of the tank Then just a normal airline fitting with a couple of big flat washers thru the inner tube and see if you can regulate the air pressure Crawl under, around on top etc and if a leak is there you'll spot it right away Paul Quote Link to comment https://www.bigmacktrucks.com/topic/63268-sucking-air-into-fuel-system-or/#findComment-455575 Share on other sites More sharing options...
fjh Posted July 11, 2020 Share Posted July 11, 2020 Also the supply pumps can fail ( Fairly common) is your oil level staying normal or rising ! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/63268-sucking-air-into-fuel-system-or/#findComment-455580 Share on other sites More sharing options...
Moneypit Posted July 12, 2020 Author Share Posted July 12, 2020 All fuel lines are good, and all injectors are good. But did find the little black plastic line on side of injector going to the front of the motor to be pinched under all the lines to be the problem I hope. I'll find out Monday when I change it. Quote Link to comment https://www.bigmacktrucks.com/topic/63268-sucking-air-into-fuel-system-or/#findComment-455650 Share on other sites More sharing options...
terry Posted July 12, 2020 Share Posted July 12, 2020 7 hours ago, Moneypit said: All fuel lines are good, and all injectors are good. But did find the little black plastic line on side of injector going to the front of the motor to be pinched under all the lines to be the problem I hope. I'll find out Monday when I change it. sounds like a return line, any hole in it will lose prime. terry Quote Link to comment https://www.bigmacktrucks.com/topic/63268-sucking-air-into-fuel-system-or/#findComment-455664 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.